For example, a known speech synthesizer generates synthetic speech based on text or pronunciation symbols which are obtained by analyzing the text.
Recently, a pet-type pet robot which includes a speech synthesizer so as to speak to a user and perform conversation (dialogue) with the user has been proposed.
Further, a pet robot which has an emotion model for expressing the state of emotion has been proposed. This type of robot follows or does not follow the order of the user depending on the state of emotion indicated by the emotion model.
Accordingly, if synthetic speech can be changed in accordance with an emotion model, synthetic speech according to the emotion can be output, and thus the entertainment characteristic of pet robots can be developed.